The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A080825 Triangle read by rows in which n-th row gives trajectory of n (omitting n itself) under the map k -> k-1 if k odd, k -> k/2 if k even. 5
 1, 2, 1, 2, 1, 4, 2, 1, 3, 2, 1, 6, 3, 2, 1, 4, 2, 1, 8, 4, 2, 1, 5, 4, 2, 1, 10, 5, 4, 2, 1, 6, 3, 2, 1, 12, 6, 3, 2, 1, 7, 6, 3, 2, 1, 14, 7, 6, 3, 2, 1, 8, 4, 2, 1, 16, 8, 4, 2, 1, 9, 8, 4, 2, 1, 18, 9, 8, 4, 2, 1, 10, 5, 4, 2, 1, 20, 10, 5, 4, 2, 1, 11, 10, 5, 4, 2, 1, 22, 11, 10, 5, 4, 2, 1, 12, 6, 3 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,2 COMMENTS If you write down 0 when divide by 2, 1 when subtract 1, the trajectory gives the binary expansion of n. LINKS EXAMPLE Triangle begins: 1; 2,1; 2,1; 4,2,1; 3,2,1; 6,3,2,1; ... 7 -> 6 -> 3 -> 2 -> 1, so the 7th row is 6,3,2,1. PROG (PARI) xnm1(n, p) = { print1(1" "); for(x=1, n, p1 = x; while(p1>1, if(p1%2==0, p1/=2, p1 = p1*p-1; ); print1(p1" ") ) ) } CROSSREFS A082404 is a better version. Sequence in context: A321368 A100380 A205403 * A229724 A034693 A216506 Adjacent sequences:  A080822 A080823 A080824 * A080826 A080827 A080828 KEYWORD easy,nonn,tabf AUTHOR Cino Hilliard, Mar 27 2003 EXTENSIONS Edited by N. J. A. Sloane, Dec 06 2008 at the suggestion of R. J. Mathar STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 29 21:18 EDT 2020. Contains 338074 sequences. (Running on oeis4.)